1 /*

     2 * Copyright (c) 2003-2009 Nokia Corporation and/or its subsidiary(-ies).

     3 * All rights reserved.

     4 * This component and the accompanying materials are made available

     5 * under the terms of the License "Eclipse Public License v1.0"

     6 * which accompanies this distribution, and is available

     7 * at the URL "http://www.eclipse.org/legal/epl-v10.html".

     8 *

     9 * Initial Contributors:

    10 * Nokia Corporation - initial contribution.

    11 *

    12 * Contributors:

    13 *

    14 * Description: 

    15 *

    16 */

    17 

    18 

    19 #include <bigint.h>

    20 #include <e32std.h>

    21 #include <random.h>

    22 #include "../common/inlines.h"

    23 

    24 

    25 /** 

    26  * Copy constructor

    27  *

    28  * This function performs a shallow copy, 

    29  * i.e. the memory holding the integer is not copied.

    30  */

    31 EXPORT_C RInteger::RInteger(const RInteger& aInteger)

    32 	{

    33 	*this = aInteger;

    34 	}

    35 

    36 /** 

    37  * Assignment operator

    38  * 

    39  * This function performs a shallow copy, 

    40  * i.e. the memory holding the integer is not copied.

    41  */

    42 EXPORT_C RInteger& RInteger::operator=(const RInteger& aInteger)

    43 	{

    44 	iSize = aInteger.iSize;

    45 	iPtr = aInteger.iPtr;

    46 	return *this;

    47 	}

    48 

    49 

    50 /** 

    51  * Creates a new integer representing 0.

    52  * 

    53  * @return	An RInteger by value.

    54  */

    55 EXPORT_C RInteger RInteger::NewL(void)

    56 	{

    57 	return NewL(TInteger::Zero());

    58 	}

    59 

    60 /** 

    61  * Creates a new integer object representing a specified value.

    62  * 

    63  * @param aValue	A descriptor containing the big-endian binary

    64  * 					representation of the value.

    65  * @return			An RInteger object representing the value.

    66  */

    67 EXPORT_C RInteger RInteger::NewL(const TDesC8& aValue)

    68 	{

    69 	RInteger self;

    70 	//Construct zero's memory beyond the size of aValue after construction

    71 	self.CreateNewL(BytesToWords(aValue.Size()));

    72 	self.Construct(aValue);

    73 	return self;

    74 	}

    75 

    76 /** 

    77  * Creates an exact copy of an \c aInteger object.

    78  * 

    79  * @param aInteger	The integer you wish to copy

    80  * @return			An RInteger object representing an exact copy of 

    81  *					aInteger by value.

    82  */

    83 EXPORT_C RInteger RInteger::NewL(const TInteger& aInteger)

    84 	{

    85 	RInteger self;

    86 	//don't need to CleanNewL as we'll copy straight from aInteger

    87 	self.CreateNewL(aInteger.Size());

    88 	self.Construct(aInteger);

    89 	return self;

    90 	}

    91 

    92 /** 

    93  * Creates a random integer uniformly distributed over [0, 2^aBits].

    94  * 

    95  * @param aBits	The number of bits you wish to randomly select.

    96  * @param aAttr	Enum specifying whether specific bits in the random number should

    97  *				be set.  See TRandomAttribute for more information.

    98  * @return		A random RInteger object in the range specified.

    99  */

   100 EXPORT_C RInteger RInteger::NewRandomL(TUint aBits, TRandomAttribute aAttr)

   101 	{

   102 	RInteger self;

   103 	self.CleanNewL(BitsToWords(aBits));

   104 	CleanupStack::PushL(self);

   105 	self.RandomizeL(aBits, aAttr);

   106 	CleanupStack::Pop(&self); 

   107 	return self;

   108 	}

   109 

   110 /** 

   111  * Creates a random integer uniformly distributed over [x | min <= x <= max].

   112  * 

   113  * @param aMin	The smallest possible value for the random integer (inclusive).

   114  * @param aMax	The largest possible value for the random integer (inclusive).

   115  * @return		A random RInteger object in the range specified.

   116  */

   117 EXPORT_C RInteger RInteger::NewRandomL(const TInteger& aMin,

   118 	const TInteger& aMax)

   119 	{

   120 	RInteger self;

   121 	self.CleanNewL(aMax.Size());

   122 	CleanupStack::PushL(self);

   123 	self.RandomizeL(aMin, aMax);

   124 	CleanupStack::Pop(&self);

   125 	return self;

   126 	}

   127 

   128 /** 

   129  * Finds a random prime integer in the range of [2, 2^aBits].

   130  *

   131  * This is done by picking a random integer and using that as a starting point

   132  * for a sequential search for a prime.  To verify the primality of number, 

   133  * this algorithm uses a probablistic primality test.  This means that it is

   134  * possible, although extremely improbable, that the number returned is a pseudoprime.

   135  *

   136  * @param aBits	The number of bits you wish to randomly select your prime from.

   137  * @param aAttr	Enum specifying whether specific bits in the random number should

   138  *				be set.  See TRandomAttribute for more information.

   139  * @return		A random RInteger representing a probable prime (with very high

   140  *				probablity) in the range specified.

   141  */

   142 EXPORT_C RInteger RInteger::NewPrimeL(TUint aBits, TRandomAttribute aAttr)

   143 	{

   144 	RInteger self;

   145 	self.CleanNewL(BitsToWords(aBits));

   146 	CleanupStack::PushL(self);

   147 	self.PrimeRandomizeL(aBits, aAttr);

   148 	CleanupStack::Pop(&self);

   149 	return self;

   150 	}

   151 

   152 /** 

   153  * Creates a new integer from the value represented by \c aInteger.

   154  * 

   155  * @param aInteger	A signed word sized integer.

   156  * @return			An RInteger representation of aInteger by value.

   157  */

   158 EXPORT_C RInteger RInteger::NewL(TInt aInteger)

   159 	{

   160 	RInteger self;

   161 	self.CreateNewL(2);

   162 	self.Construct(aInteger);

   163 	return self;

   164 	}

   165 

   166 /** 

   167  * Creates a new integer from the value represented by \c aInteger.

   168  *

   169  * @param aInteger	An unsigned word sized integer.

   170  * @return			An RInteger representation of aInteger by value.

   171  */

   172 EXPORT_C RInteger RInteger::NewL(TUint aInteger)

   173 	{

   174 	RInteger self;

   175 	self.CreateNewL(2);

   176 	self.Construct(aInteger);

   177 	return self;

   178 	}

   179 

   180 /** 

   181  * Creates a new integer with a preallocated internal storage of \c aNumWords all

   182  * initialised to zero.

   183  *

   184  * The resulting RInteger object is logically equivalent to RInteger::NewL(0).

   185  * The only difference is that the internal storage requirements have been 

   186  * specified to be larger than the default. This is useful if you are about 

   187  * to perform an operation on this integer, that you know the resulting size

   188  * requirements of, and wish to avoid a heap resize.

   189  *

   190  * @param aNumWords	The number of words for to preallocated and zero fill.

   191  * @return			An RInteger object representing 0 with a preallocated 

   192  *					zero-filled internal storage of aNumWords.

   193  */

   194 EXPORT_C RInteger RInteger::NewEmptyL(TUint aNumWords)

   195 	{

   196 	RInteger self;

   197 	self.CleanNewL(aNumWords);

   198 	//There's no construct as there isn't anything to do

   199 	return self;

   200 	}

   201 

   202 /**

   203  * Creates an RInteger object with no associated internal (heap) storage.

   204  * 

   205  * All data members are initialised to zero.  It is safe (although not strictly necessary)

   206  * to push such an RInteger object onto the CleanupStack.  This is useful, for example, if

   207  * you want to pass an RInteger object by reference into a function and have it create

   208  * the representation of the actual integer for you.  

   209  *

   210  * Note that performing any operation on such an RInteger object other than the default

   211  * assignment operator or copy constructor will panic your code.

   212  * 

   213  * @return	A stack based class that has no associated internal storage and thus

   214  *			does not represent any number.

   215  */

   216 EXPORT_C RInteger::RInteger(void)  

   217 	{

   218 	}

   219 

   220 /** 

   221  * An overloaded TCleanupItem() allowing the RIntegers to be pushed,

   222  * popped, and destroyed via the CleanupStack like any other CBase derived object.

   223  */

   224 EXPORT_C RInteger::operator TCleanupItem(void)

   225 	{

   226 	return TCleanupItem(&RInteger::CallClose, this);

   227 	}

   228 

   229 /** 

   230  * Helper function registered with the cleanup stack that just calls Close() for

   231  * this RInteger object.

   232  * 

   233  * @param aPtr	A pointer to the object for which clean-up is to be performed. 

   234  */

   235 EXPORT_C void RInteger::CallClose(TAny* aPtr)

   236 	{

   237 	((RInteger*)aPtr)->Close();	

   238 	}

   239 

   240 /** 

   241  * Zeros and then frees any memory owned by this RInteger object.

   242  *  

   243  * An RInteger object that has been closed can safely fall off the stack.

   244  */

   245 EXPORT_C void RInteger::Close(void)

   246 	{

   247 	if (iPtr)

   248 		{

   249 		Mem::FillZ(Ptr(), Size()*4);

   250 		User::Free(Ptr());

   251 		iSize = 0;

   252 		iPtr = NULL;

   253 		}

   254 	}